Allyl iodide, oxidation, yield

Allyltin difluoroiodide, formed in situ by the oxidative addition of stannous fluoride to allyl iodide, is found to react with carbonyl compounds to give the corresponding homoallylic alcohols in excellent yields under mild reaction conditions (9). 

Oxidation of allylic iodides to rearranged allylic alcohols. The oxidation of R1 to ROH hy m-chloroperhenzoic acid (8, 98-99) has been extended to oxidation of allylic iodides. In this case the presence of a base (NaHCO,) is necessary for satisfactory yields, and at least 3 equiv. of the peracid is necessary. The oxidation involves a [2,3] sigmatropic rearrangement. 

Direct reaction of Mg and at elevated T and P yields MgHj. The rate is slow, and the process is difficult to carry to completion because the metal particles become coated with a dense layer of the hydride, through which the Hj must diffuse. If the T is raised to increase the diffusion rate, the dissociation P is also increased and, for the reaction to proceed, the ambient Hj P must exceed the dissociation P e.g., 40 MPa and over 500°C are employed To increase the rate and facilitate complete reaction, various catalysts, such as Ij CCl allyl iodide and Mglj are used. Intimate mixing of LaNij MgjCu or Fe " with Mg metal decreases the time needed to complete hydride formation e.g., the addition of 20% LaNij increases the percentage completion after 15 min (at 345°C) from ca. 12% for pure Mg, to over 80% for the mixture . These latter three catalysts provide an oxide-free surface to facilitate dissociative adsorption of the Hj. 

Figure 2. Yield of acrolein and CO2 in oxidation of propylene and allyl iodide as function of the coverage of Mo0 with bismuth ions. (Reproduced with permission from Ref. 23.) ...

PtPh2(bipy)] reacts with HBF4 in acetonitrile to give cationic [Pt(Ph)(bipy)(AN)](Bp4) (020M2088). [Pt(Ph)I(bipy)] reacts with silver tetrafluoroborate in acetone or acetonitrile to yield [Pt(Ph)(bipy)(sol-vent)](Bp4) (solvent = acetone, AN). Under carbon monoxide, the latter transform into the carbonyl complex [Pt(Ph)(CO)(bipy)](Bp4). The acetone complex inserts phenylallene into the platinum-phenyl bond to yield 85. Under carbon monoxide, 85 readily rearranges into cr-allyl 86. [Pt(Ph)(bipy)(AN)](Bp4) oxidatively adds methyl iodide to yield [Pt(Ph)(bipy)(AN)(Me)(l)](BF4). 

In the presence of bismuth(lll) chloride-aluminum, allylic bromides have been found to react with aldehydes at room temperature in tetrahydrofuran-water to afford the corresponding homoallyhc alcohols in high yields (Wada et al, 1987). Water was found to play a crucial role since the allylation failed in pure tetrahydrofuran. Only a catalytic amount of bismuth chloride was needed to carry out the reaction. Bismuth(ill) chloride was reduced by aluminum to zero-valent bismuth, which could insert into the carbon-bromine bond of the allylic bromide to afford an allylbismuth intermediate as the reactive species. The allylation reaction could occur with the couple Bi(0)-Al(0) in tetrahydrofuran-water only in the presence of a catalytic amount of hydrobromic acid (Wada et al, 1990). Since bismuth(O) was postulated to be an intermediate oxidation state, the reaction was accomplished via an electrochemical redox pathway (Figure 4.1) in a two-phase system (Minato and Tsuji, 1988). Reactions mediated by Bi(0) as the only promotor were sluggish (Wada et ah, 1990). An exception was, however, reported with the coupling between p-nitrobenzaldehyde and allyl iodide in water (Chan and Isaac, 1996). 

Similarly, the oxidation of iodocyclohexane by DMD under a nitrogen-gas atmosphere leads to the iodohydrin and diol as unexpected products (equation 24). The iodohydrin, formed as the major product, clearly reveals that hypoiodous acid (HOI) is generated in situ, which adds to the liberated cyclohexene. Indeed, when methyl iodide (Mel) is oxidized by DMD at subambient temperature in the presence of cyclohexene, the corresponding iodohydrin is obtained in very good yield The latter method may be utilized for the preparation of allylic alcohols with a vinylic iodo functional group from allenes (equation 25) . ... 

Another total synthesis of sufentanil has been described the cyclization of 2-(2-thienyl)ethylamine with allyl-trimethylsilane and formaldehyde gives 4-hydroxy-1-[2-(2-thienyl)ethyl]piperidine, which is oxidized with oxalyl chloride in DMSO/dichloromethane to 1-[2-(2-thienyl) ethyl]piperidin-4-one. The epoxidation of this compound by means of trimethylsulfonium iodide and the sodium salt of DMSO yields the spiro-epoxide, which is opened with... 

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